Impotence is the inability to obtain and sustain an erection sufficient for intercourse. The penis becomes erect when certain tissues (in particular, the corpora cavernosa) in the central portion of the penis becomes engorged with blood thereby causing them to become less flaccid, and in turn causing an erection. It is estimated that 10-12 million American men between the ages of 18 and 75 suffer from chronic impotence with the great majority being over the age of 55.
Impotence results from psychologic disturbances (psychogenic), from physiologic abnormalities (organic) or from a combination of both. Typically, multiple factors are responsible for impotence.
The major causes of organic impotence are vascular abnormalities, neurologic deficiencies and drug treatment side effects. The primary vascular causes of impotence are arterial insufficiency, which prevents the penis from filling with blood, and venous abnormalities that prevent the retention of blood in the penis during the erectile process. Arterial insufficiency is primarily due to atherosclerosis and has been found to be exacerbated by smoking. A less frequent and somewhat unlikely vascular cause of impotence is priapism, prolonged painful erection, which can cause hypoxia and death of penile tissue.
The search for impotence treatment methods has included external devices for example, tourniquets (see U.S. Pat. No. 2,818,855). In addition penile implants, such as hinged or solids rods and inflatable, spring driven or hydraulic models, have been used for some time. The administration of erection effecting and enhancing drugs is taught in U.S. Pat. No. 4,127,118. That patent teaches a method of treating male impotence by injecting into the penis an appropriate vasodilator, in particular, an adrenergic blocking agent or a smooth muscle relaxant to effect and enhance an erection. More recently U.S. Pat. No. 4,801,587 teaches the application of an ointment to relieve impotence. The ointment consists of the vasodilators papaverine, hydralazine, sodium nitroprusside, phenoxybenzamine, or phentolamine and a carrier to assist absorption of the primary agent through the skin. In addition, Yohimbine, an alpha adrenergic antagonist is currently marketed with the suggestion that it may be efficacious in treating psychogenic impotence.
Although the injection of such agents as papaverine into the corpora cavernosa has proven effective, typically large doses 8 to 32 mg are required, resulting in undesired side effects such as pain, priapism and tissue fibrosis. The other impotence relieving agents also have one or more of the above problems when administered intracavernosally.
Thus, there is a continuing search in this field of art for improved methods for relieving male erectile impotence.